The present invention relates to a method for transportation of pulverulent filling material through a line, and in particular, micronized filling material. The invention also relates to a device for carrying out the method.
Pulverulent filling materials may be foodstuffs and luxury items, such as, for example, coffee powder, cocoa powder, and the like. Alternatively, the filling material may be a pharmaceutical, in which case the filling material may contain very small nonflowable pulverized particles, or consist solely of such. In particular, powders used as pharmaceuticals are commonly taken by the patient in the form of what is known as “micronized powder” in very small quantities of 2 to 20 mg (milligrams). Such micronized powders commonly have a particle size of between 0.5 micrometers and 5.0 micrometers and below. Such powders can agglomerate to a very great extent, so that, in technical terms, they cannot be transported and introduced into containers in a simple manner.
German patent document DE 102 47 829 A1 discloses a method and device for the pneumatic conveyance of pulverulent material through a line. The pulverulent material is acted upon alternately by underpressure and overpressure, and is thus alternately sucked into and pressed out of a line section. Action by gas underpressure and gas overpressure requires a filter element. The finer the pulverulent material is, the more quickly such filter elements clog up. In order to maintain the performance and continuity of the powder transport through the line, the overpressure has to be increased continuously in response to the clogging of the filter element. An attempt is made to reduce the degree of contamination of the filter element (and thereby lengthen its useful life) by designing the filter element in such a way that it surrounds, as a hollow cylinder, the section of the line acted upon by the underpressure and overpressure.
Filling devices, such as the types known from German patent documents DE 202 09 156 U1 and DE 102 26 989 A1, are commonly supplied with such pulverulent filling material through lines of this type. Pulverulent filling material is introduced from the filling devices into individual containers in predetermined metered quantities. An interruption in the operation of such filling devices, such as may occur, for example, during cleaning work on the above-mentioned filter element which is no longer sufficiently gas-permeable, is highly undesirable.